Bacteria spend most of their time growing extremely slowly. This project is directed toward the special problems this presents to the organisms and their response thereto. Ongoing projects have to do with the kind and state of the RNA present in slow growing cells. We know that the amount of RNA is in excess in such cells, and is present in the same amount no matter what factor limits growth. We know that different limitations alter the effectiveness of that RNA in being capable of functioning in protein synthesis. Another experimental project has to do with the initiation of cell division at slow growth rates, and the mechanism of DNA replication. In the population biology of ecosystems, such as the gut of a mammalian organism, we are engaged in studying the state of regulatory genes in natural populations as a function of the kind and nutritional state of the host. Theoretical studies are ongoing which suggest that microorganisms may resist invasion from outside the ecosystem by mutation and selection for regulatory genes. Studies of the transport of sugars are continuing with a special emphasis on the accumulation from extremely low external concentrations.